Since the iPad doesn't have a USB port or SSD card slot (can I say "grrrr!' again?) Apple sells a Camera Kit that's supposed to let you plug in your camera or card and transfer your pictures and video -- but also used to work for low power USB keyboards and Skype/VoIP headsets. I say "used to" because with iOS 4.2 that no longer seems to be the case.
Mark Gurman from 9to5mac has done some tests:
The essence of the issue with the connection kit and iOS 4.2 is that connected devices that require power of more than 20mA will no longer work. That means that many USB keyboards (Apple’s included) will no longer work with the iPad, as well as USB flash drives. When the user connects a device that is not self-powered and requires more than 20mA of power from the iPad they get the following alert: “The connected USB device requires too much power.”
Support for those devices was unofficial but it was useful. Worse news for photographers, power-hungry cameras seem to be having issues as well. And really, what good is a Camera Kit if your camera won't work as you've come to expect? Hopefully this is a bug and Apple will fix it in iOS 4.3 (I'm adding it to my list!)
We spoke about this on the last iPad Live podcast, and we've gotten some angry emails and tweets about it already but if you're having any issues with your iPad Camera Kit, give us the details in comments.